In the construction of pipelines or in directional drilling, it is necessary to load and offload large, unwieldy pipes from flatbed trucks. The weight of a pipe will vary depending on the diameter, wall thickness, and length, with some pipes weighing several hundred pounds per linear foot.
At the construction site, each pipe is individually lifted from or loaded onto the bed of a truck, rail car or pipe rack. Normally, nylon straps and cables, with or without manual calipers, are secured around the pipe than attached to the bucket of an excavator. The calipers or nylon straps are placed, as close as possible, at the longitudinal center of the pipe. This is important since being off-center, even by a few inches, results in decreased control and unwanted tilt of the pipe. In addition, it is necessary to station at least one worker at each end of the pipe to steady and guide the pipe as it is moved into location. The workers then manually tilt and rotate the pipe into position. This is cumbersome and dangerous which requires three or more workers (excavator operators and two pipe workers).
Pipe hooks are also used to manipulate the pipe. The pipe hooks are located at each end of the pipe and are attached to cables. A worker is provided at each end of the pipe to place the hooks and control the motion of the pipe. When unloading the pipe from the truck in this manner, it is dangerous for the worker as the worker can easily fall off of the truck or be hit by or crushed by the pipe.
Current pipe loaders also require that pipes be loaded/offloaded in a certain order and that spacing be provided between pipes so that the calipers are able to access the areas next to and under the pipes. Even so, it is not uncommon for pipes to be knocked free of the pipe pile, causing dangerous conditions or damaging the pipe.
Pipeline vacuum lifts are also used to lift large diameter pipes. While a vacuum lift eliminates the need for workers at each pipe end, the vacuum lift needs to be generally centered on the pipe to avoid tilting of the pipe. If the vacuum lift is not centered properly on the pipe, an off center lift occurs creating a tipping movement. This tipping movement can break the vacuum seal between the vacuum lift and the pipe or result in dangerous tilting and loss of control of the pipe. In addition, loss of suction or vacuum power can result in release of the pipe from the vacuum lift resulting in dangerous conditions. In addition, in order to obtain an effective seal of the vacuum lift, the surface of the pipe must be clean without the presence of any dirt, snow or ice.